Radius and strength sliders in pie menus
From the link as it may help others to see it directly - borrowed from Pitiwazou's post on Blenderartists.org:

def draw(self, context):
    layout = self.layout
    pie = layout.menu_pie()

    ups = context.tool_settings.unified_paint_settings
    sculpt = context.tool_settings.sculpt

    col = pie.column(align=True)        
    col.prop(ups, "size", text="Radius", slider=False)


    col = pie.column(align=True)        
    col.operator("sculpt.sample_detail_size", text="", icon='EYEDROPPER')
    col.prop(sculpt, "constant_detail")